1. Field of the Invention
The present invention relates to a head suspension for a disk drive installed in an information processing apparatus such as a personal computer and a method of manufacturing the head suspension.
2. Description of Related Art
Small-sized, precision information devices are rapidly advancing, and for use with such devices, needs for micro-actuators capable of conducting positioning control for very small distances are increasing. Such micro-actuators are highly needed by, for example, optical systems for correcting focuses and inclination angles, ink jet printers for controlling ink heads, and magnetic disk drives for controlling magnetic heads.
To meet the need, Japanese Unexamined Patent Application Publication No. 2002-50140 of this applicant has proposed a head suspension for a disk drive. The head suspension includes a base plate, a connection plate having a hinge thinner than the base plate, a load beam that is provided with a flexure, and a piezoelectric actuator having a pair of piezoelectric elements.
This related art employs a dual actuator system that involves, for a precise positioning purpose, a voice coil motor and the piezoelectric actuator having two piezoelectric elements made of, for example, PZT (lead zirconate titanate).
The piezoelectric actuator in the dual actuator system minutely moves a front end of the load beam in a widthwise direction (sway direction) of the head suspension. Compared with a single actuator system employing only the voice coil motor, the dual actuator system employing the voice coil motor and piezoelectric actuator is capable of more precisely positioning a magnetic head attached to a front end of the head suspension.
An important issue for the head suspension employing the dual actuator system is how to supply power to the piezoelectric element.
One approach to address the issue is disclosed in Japanese Unexamined Patent Application Publication No. 2003-61371. This related art forms a pair of wires and connects one of the wires to a first electrode of the piezoelectric element by wire bonding and the other wire to a second electrode of the piezoelectric element by wire bonding and supplies power through the wires to the piezoelectric element, as illustrated in FIGS. 9 and 10 of the related art.
The wire bonding of this related art, however, applies local stress onto the piezoelectric element to secure bonding strength. Applying local stress onto the piezoelectric element involves a risk of damaging the piezoelectric element. If the wire bonding is carried out moderately to prevent the damage of the piezoelectric element, the bonding strength will be insufficient and deteriorate the reliability of electrical connection.
It is difficult for the related art to prevent the breakage of the piezoelectric element, and at the same time, secure the reliability of electrical connection between the power supply wiring and the piezoelectric element.